Lighter-than-air craft



` Feb. A14, 1928.

" /r B. N. WALLIS LIGHTER-THAN-AIR CRAFT 4 Sheets-Shea 3 Feb.14,192s. y Y 1,658,821

, l B. N. WALL-ls gV Filed- Jam 5. 1925 4 Sheeis-Sneet 4` fw. A, l

f. ,111111'111'W11W1l1' 10m mwmmmnw mmm ATTORNEYS paci vEn() Patented Feb. 14, 1928. y

i i i l 1,658,821

UNITEDsrarssraranr OFFICE.,

BARNES NEVILLE WALLIS, GF WESTVMNSTER, LONLON, ENGLAND, ASSIG-NOR TO `AIR- SHIP GUARANTEE COMPANY, LIMITED, OF lWTESTMllSrLlElR, ENGLAND, A BRITISH coMrANY.

' Application filed January 23, 1925, Serial No.

This invention relates to lighter-than-air craft.

As is well understood the resultant normal pressure on the inner surface of the .gas bag or bags oigan airship is greater at the `top `of the 'bagthan atv the bottom, equaling approximately .Olbs to the square foot per toot rise in height from Zero or approximately zero at the` bottom or' the bag to the maximum pressure at thetop of the bag.

AAs the gas bags or aerostats are usually adapted to lpress freely on a flexible network and, as the wires `or ropes comprising they network are invariably of uniform pitch throughout both in the high and low pressure areas, each bag tends to take up a socalled elastic curvature 0r to bulge the network outwards in the high pressure Zones of the bag. Consequently, the load is unevenly distributed and unequal strains are set up in the framework, in the case of a rigid ship. Moreover, owing to the unequal distribution of the lifting forces on the framework, undue bending stresses are thereby set up in va rious partsl of the structure. Furthermore, owing to the space taken up by the bulge of the surface of the gas bag or aerostat dueto the elasticy curvature of the restraining network between consecutive and adjacent structural members, it has notbeen possible to use gas bags of the largest capacity attainable for a given diameter or" airship.

Accordingly,` it maybe said that the cav and performance ot' rigid airshipsl'rave heretofore been reduced 'below what may otherwise have been possible owing to the absence or' anyjeiiicient method of controlling the shape and evenly distributing the lii't of the `bags from their iexible enclosing networks to the framework of the airship.

In the case ot nonrigid or semi-rigid airships the shape of the airship is morek or less determined by the shape of Vits 'aerostats,

and owing to the latter taking up the socalled elastic curvature and bulging the network outwards inthe high ypressure zones the speed and navigability of the air-ship are reduced. c f f According to the present-invention any desired shape orrsiZe of airship, ballon or dirigible may be' produced-by varying in differ-k entsections or zones the pitch 'of the wires treuren-,risanare cia-Arr.

4,161, and in Great Britain January 26, 1924.

comprising the flexible network which encloses the aerostat, the wires of each zone or section being also ot such la selected pitch that, when subjected tok the pressure of lthe fully inflated aerostat, the network takes up itsdesired curvature or camber. Forexample, when it is desired that the network, or each network in the case of airships having a plurality oi separate gas bags, when subjected to the pressure of the fully inflat-ed .aeros'tat or aerostats, shall be circular or substantially circular in cross section, the tension of the wires comprising the network is maintained equal and in equilibriumrby progressively increasing the 4pitch of the ,vlres from the high pressure Zones atthe top of the bag to the low pressure Zones at the bottom thereof, thus obtaining what might be termed an isotonic or equal tension effect throughout the wires of the enclosing network. In such cases the wires comprising the network will spread out alongnonparallel lines or in anlike formation from a selected minimum distance apart at the vtop of the gas bag where the pressure is greatest .to themaximum distance apart at the bottom of the bag where the theoretical pres sure is Zero. Any desiredsystemof mesh wiring can be adopted. It is preferred, however, kto arrange the wires ofthe network so that they follow approximately a spiral or helical path around the airship. In the case `of a rigid airship having a plurality of polyh gonal sides or sections each wire of the network enclosing or surrounding a gas bag may have one of its .ends connected to a catenary the latter in turn being attached at itsends to a transversepframe, usually atthe points where they meet the longitudinal frames. The other end of each mesh wire may be attached to a locating wire disposed parallel to the longitudinal.frames said locating wire being attached at its ends t0 the vided yeach composed, .for example, of a length of wire ormed with 'eyelets spaced Iaoart`r at a distance corresponding to the desafedpitchcf the wires .in particular Zone, panel or section. The network may, in the first instance, be built up in sections by attaching the wires to the locating wires, the network being then placed in position and attached to the transverse frames.

The same result, i. e. the ability to control the shape of the aerostat at will, may also be. attainedby varying the tension in each wire in relationship to the angle of inclination of the wire to the longitudinal axis of the ship, the load per foot run of wire being maintained constant, or at any desired figures, throughout all wires by the method previously described. Each wire in development now lies in a straight line, the wires radiating fanwisc from the top or upper panel of the aerostat.

A further method in which the risotonic principle is retained is to vary both the load per foot run in contiguous wires and the angle of inclination to the longitudinal axis of the ship in such a manner that the wires will tend to deflect to such a shape that their projection on a right transverse section is the are of a circle whose radius is equal to the radius of the gas bag.

The aforesaid arrangements may be employed with a reduced number of transversely disposed attachment wires and with or Without the catenaries above referred to.

The network may be built up by attaching the wires to eyelets, attachments or other connecting devices, provided on the transverse frames, or on locating wires provided on the transverse frames, the eyelets or attachments for the wires being spaced apart at the required distances.

In order to obtain the isotonic effect and, having found the value of PXAK, where P is the resultant normal pressure on the inner surface ofthe top ot' the gas bagand A tie area supported per unit. length olf wire, the pitch p of the wires in any particular Zone or section can be determined by the general formula Prie where P is the resultant normal pressure on `the gas bag in the zone where. the pitch ot the wires is to be determined In order that the said invention may be clearly understood and readily carried into effect the same will now be described more fully with reference to the accon'ipanying drawings which show dia-grammatically and by way of example a number ot dillerent embodiments of the invention, and in which z lFigure 1 `shows a development of half of one of the networks which surrounds agas bag of a rigid airship, the cross section of the airship to which the network is applied being thatof a fourteenesided polygon 129 feet in diameter and Where, therefore, there is a resultant normal pressure at the top of the bags of approximately 8.2 lbs. per square foot.

Figures 2, 3 and 4l show in development three modified forms of the invention wherein the isotonic principle is retained without the use of ay complete series of longitudinal locating wires 2, 2. In these constructions, therefore, only two locating wires 2, 2 are employed these wires being positioned respectively at the top and the bot-tom of the airship and running parallel to the main longitudinal girders, at these points certain f the wires of the network having` one of their ends attached to the locating wires 2, 2 and the other end attached to one of the transverse frames l, l, while other wires of the network, have both their ends attached to the contiguous transverse frames l, l. The `wires 8, 8 which are shown stretching between the frames l, l, at VFigures 2, 3 and l are merely provided to assist in constructing the network in situ yas also to prevent the collapse of the network when the gas bags are not fully inflated.

Figure 5 is a sectional end y'iew showing a network constructed on the isotonic principle and located transversely between a pair of contiguous gas bags, and

Figure 6 is a detail view showing the method which may be adopted in pivotally attaching the network shown at Figure 5 directly to the transverse frames l, l.

Figure 7 is a longitudinal section showing a gas bag G in place between a pair of transverse net-works, H, H.

Fig. 8 is a. sectional view showing diagram'matically the position of the passenger cars.

Fig. Q shows a n'iodilied arrangement in which thc mesh wires are attached to the transverse frames oit' the airship by means 0f eatenarics. and wherein intern'iediate ab tachment wires are also provided.

ln the example shown at Figure l each section.` or panel A, B, C, D, E. if, G of the enclosing liexible. network has a length oi 63 feet, i. e. the distance between a. contiguousI pair of transverse framers l, l: and a length of side of polygon of 2S) feet, i. e. the distance between each pair of locating wi n.' 2, 2. The pitch oit' the wires in the top sec* tion or panel A is appresimately 1T inches; in section ll, [7.7 inches; in tion (l. 2() inches; in section l), 24.6 inc on E, 33 inches; in section F, 47.7 inches; in section G. 69 inches and in section H. 83.5 inches. The other half of the network on the opposite half of the gas bagwill be ol' similar construction.

The wires where they cross one another are bound together in any suitable manner, for example, by means of rubber tape.

Figures 2, 3 and Ll show the eti'ect of adopting different helix angles in cases where Jthe lift) Aload per foot run in contiguous wires as' alsoy the angle of inclination of the wires to the longitudinal axis of the ship is varied continuouslyfrom the top to the bottom Yof the bag. In the example shown at vFigure 2 the pilot wires 4 and 5 have a helix angle of 72 degrees with reference to the longitudinal axis oit' the airship; in the example shown at Figure 4 the pilot wires 6 and 7 have a helix angle et 61degrees, and in the example shown at Figure 5 the pilot wires 8 and 9 have a helix angle of degrees. i

Onlyone half of the mesh wiring has been shown f'or the sake of clearance but the other'half of the niesh is identical with the :portion shown. The correct variation of each wire so as to obtain the isotonic effect and cause each wire to deflect to the required are may be determined by the formula or it may be obtained from the arrangement shown at Figure 1, by positioning each wire at an angle of' inclination which is a mean of that any of the wires that extend beyond .more than one polygonal section. It may be shown that tot@ Where 0 is the angle of inclination which the pilot wires 4, 5 etc., make with the transverse frames 1, 1; The greater 0 the less is the tension of the wires of the mesh wiring and the greater is the lateral pull on thevlongitudinal wires situated at the top and bottom of the bag.

` Further, the greater 6 theiless is the longitudinal component in the `longitudinal frames and the less is the side pull on the main transverse frames 1, 1. The wires haveequal tension throughout the VVcircumference of any given gas bag'thus giving a substantially tangential componentat the points of attachment to the structure with no radial component. i

lhere fiexible l networks' have heretofore been employed the load is usually transmitted tothelongitudinalraniesas a distributed lateral loading which in turn is transmitted to the transverse frames and thence by suspension wires to the bottom or keel oi the airship where the passengercars, etc., are usually located, whereas the novel construction of network herein described, has the advantage thatthe reactions obtained at the wire terminals are substantially tangential and, as aforesaid, the load is transferred to the transverse frames as a substantially tangential component, consequently, `tangential loading canbe resorted to and the passenger cars, etc., may belocated atthe sides of the airship where the maximum lifts are obtained. Such an arrangement is shown diagrammatically in Fig. Siwherein the cars M, M are suspended by cables M', M from the `rigid frame work of the airship. Instead of` being connected directly to the transverse frames 1, 1, the mesh wires may beV connected to catenaries 1, 1a; intermediate attachment wires 1b, 1b, being also provided.

This location of the main loads, such as the passenger cars,has the advantage that interference with the cont'rollability ofi the airship (sometimes referred to as fin effect) is avoided, as, when passenger cars are suspended f'romthe keel of the airship, as is usually the case, the tendency of the airship to yaiv is Vincreased by the fin-like action of the cars, and, consequently, the size of' the vertical fins and rudders has to be increased proportionately to correct this tendency. In cases, therefore, wherethe passenger cars are `slung from the sides of the airship the size of the'vertical fins and controlling rudders need not be increased. i

As the main loads are attached to or supported from the sides of the airsliip, in contradistinction to ships of the Zeppelin and other types where the loads are dis tributed on the 'underside of the airship, an airsliip of larger size Vcan be built in a shed of the same size* as that required for a much smaller airship of the existing types, as space for the cars at the bottom ofthe keel does not require to be provided for.

It will be clear that it will not only be possible by the present invention to produce anv airship or the like of'any desired cross section, but also anV airship or the like the shape or configuration of which can be varied at different points along its length so as to obtain the best streamline effects while at the same time preserving the-advantage ofv aflexible enclosing networkhaviiig soecalled isotonic effects. Y

In all the above cases it has been assumed that the shape to which it isdesired to con-Y strain the aerostats orthe gas bags is substantiallya circular shape.YV It will be under stood however, that the true shape to which each ,wire must conform is not strictly the larc ot a circle, but Vapproximates more closely to the arc of an ellipse.

In cases Where a network H is provided and disposed transversely of the airship as shown at Figures 5, 6 and 7 the wires 14, 14 may have no initial tension and may be pivotally attached at their ends (as shown at Figure 7), to the transverse Jframes 1, 1.

-On a gas bag becoming deflated, however, the pressure of; the contiguous bag G will cause the network 'to deflect to the arc of acircle (as shown in chain lines at I `Figure 7) and not-to an elastic curve so' thatthe load ,per foot run of each wireivill be constant and norinaland 'distributed eveiilyftoV the framework of the airship.-

The transverse frames and the' longitudiieu nal frames shown at Figuresand 7 may be constructed inthe manner described inv my] co=pending United States application Serial No. 4,504, the transverse frames being constituted by built-up space frame girders which possess great lateral stiffness and in which internal bracing wires can bedispensed with.

TWhat I claim and desire to secure by Letters Patent of the United States is l. An airship, or dirigible comprising an eerostat which. is non-circular in any horizontal cross-section and in which the mesh of the network which surrounds the aerostat 'orooressivelv.increases from the high aressure Zones at the top of the aerostat to the low pressure zones at the bottom thereof.

2. An airship or dirigible comprising a plurality of aerostats surrounded by a net-- work, the mesh of which progressively increases from the high pressure zones at the top of the aerostat to the low pressure Zones at the bottom thereof.

3. A rigid airship in which the mesh of the network which surrounds the aerostat vprogressively increases from the high pressure Zones at the top of the aerostat to the low pressure zones at the bottom thereof.7 each wire of the network stretching between and having its ends attached to a contiguous pair of transverse frames.

4:. An airship or dirigible comprising an aerostat which is non-circular in any horizontal cross-section, and in which the pitch of the wires comprising the flexible network surrounding the aerost-at is varied in different zones. An airship or dirigible'comprising' a plurality of aerostats each surrounded by a flexible network and wherein the pitch of the wires comprising the lflexible network surrounding each aerostat is varied in different zones.

6. An airship, balloon or dirigible in 'which the tension in the wires of the network which encloses the aerostat is variedV in relationship to the angle of inclination of the wiresto thelongitudinal axis of the ship, and in which the load per foot Yrun of each wire is maintained constant or at any desired figure by progressively increasing the pitch of the wires from the high pressure zones at the top of the aerostatto the low pressure zones at the bottom thereof.

7. An airship, balloon or dirigible which the tension of the wires compr' the enclosing network for the aerosta`y is maintained equal by 'varying both the load per foot run in contiguous wires `and the angle of inclination of the wires to the longitudinal axis of the ship so that each wire tends to deflect to the desired arc.

8. An airship, balloon or dirigible, in which the pitch of the wires of the mesh wiring which surrounds the aerostat is progressively increased from the high pressure zones at the top of the aerostatto the low pressure zones at the bottom thereof, -each wire being located at lsuch a selected pitch that the load per footv run is constant and normal so that the wires under the pressure of the fully inflated aerostat deflect approximately to such a shape that their projection on a right transverse section is the arc of a circle whose radius is equal to the radius of the aerostat.

9. An airship as claimed in claim l in which the main loads such as the passenger cars, are located at the sides of the airship where the maximum lifts are obtained.

l0. A rigid airship provided with transverse frames and; with a network the wires of which stretch transversely across and are connected at their ends to said frames so to provide a. network between a contig,- uous pair of gas bags, the mesh of said network progressively increasingr from the top to the bottom of the airships.

ll. An airship in which the mesh of the network which surrounds the aerostat progressively increases from the high pressure zones at the top of the aerostat to the low pressure zones at the bottom thereof, each mesh of the network being formed by four members which are inclined relatively to the transverse. frames of the airship, each member stretching between and being 'connected at each of its ends to a contiguous pair of transverse frames.

l2. An airship as claimed in claim l1 in which intermediate longitudinally disposed attachment members are also provided.

13. An airship, balloon or dirigible in which the pitch of the 'wires comprising the flexible network or networks surrounding the aerostat or aerostats is varied in difl'erent Zones or sections, in such manner that when subjected to the pressure of the fully inflated aerostat or aerostats the network or each network takes up the Adesired curvature or camber and in which the wires are attached intermediately of their length to a longitudinally disposed member or members.

14. An airship, balloon or dirigible vof any desired shape in lwhich the tension of the wires comprising the enclosing network or networks for the aerostat or aerostats is maintained equal by varying both the load per foot run in contiguous wires and the angle of inclination of the wires to the longitudinal axis of the ship so that each wire tends to deflectto the desired arc. the wires being attached intermediately of their length to a longitudinally disposed member or members.

15.An airship, balloon or dirigible, in which` the pitch of the wires of the mesh wiring is progressively increased from the high pressure zo-nes at the top of the aerostat to the low pressure zones at the bottom thereof, each wire being located at such a selected pitch that the load per foot run is constant and normal so` that the wires under the pressure of the fully inflated aerostat deflect approximately to such a shape that their projection on a right transversesection is the arc of a circle whose vradius is equal `to the radius of the gas bag.. the wires being attached intermediately of their ends toa longitudinallyv disposed member or members. v

16. An airship, balloon or -dirigible in which the Wires comprising the network which encloses the aerostat are of such a selected pitch that the tension thereof isl lmaintained equal or at any desired figure or in which the network spreads out along non-parallel lines or in fan-like formation from a selected minimum distance apart at the top of the gas bagsrwhere the pressure is greatest to the maximum distance apart at the bottom ofthe bag where the theoretical pressure is zero, the wires being attached intermediately of their length to a longitudinally disposed member.

17. An airship in which the load is transferred to the transverse frames in the case of a rigid airship, or to the fabric which encloses the aerostat in the case of a nonrigid or semi-rigid airship7 as a tangential component, by progressively'increasing the pitch of the wires from the high pressure Zones at the top of each aerostatorgas bag to the low pressure zonesv at the bottom thereof, the wires'being attached intermediately of their length to a longitudinally disposed member or members or to a longitudinally disposed locating strip orl strips.

18. An airship in whichv the mesh of they networks which enclose the gas bagsl progressively increases from the khigh pressure zones at vthe top of the bags to the low pressure zones'at the bottom thereof and inv which the reactions obtained at the Wire terminals are substantially tangential, the wires *beingy *attachedv intermediately of their length to longitudinally disposed members.

19. An enveloping networkvfor the gas bags of rigid airships in which the pitch of the wiresprogressively increases from the top to the bottom of each gas bag and' in which each wire in attached intermediately of its ends to a locating member disposed `parallel to thelongitudin'al frames. f QOJAn enveloping network forthe gas bags of rigid airships las claimed in claim 19 in which the ends of the locating members are Vattached to the transverse frames atthe points where they meet the longitudinal frames. i

21. An enveloping network for the gas bags of a rigid airship in which the pitch of the wires continuously increases from the top to the bottom ofthe bag and in which two locating wires are provided located respect-ively at the top and bottom ofthe airship7 the wires of the networkat these points being attached intermediately of their length to said locating wires.

. 22. An airship in which the mesh of the network which lsurrounds the aerostat pro-y gressively increases from the highy pressure Zones at the top of the aerostat .to the low pressure ,zones at'the bottom thereof, each mesh lof the network being formed by four members which are inclined relatively to the transverse frames of the airship, each member stretching between and being connected at each of its ends to a contiguous pair of transverse frames through the intermediary of catenaries.' V

23. An airship as'claimed in claim 22 in which intermediate longitudinally disposed attachment members are also provided."

p BARNES NEVILLE WALLIS. 

